/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package org.jboss.netty.channel;

import java.io.IOException;
import java.nio.channels.FileChannel;
import java.nio.channels.WritableByteChannel;

public class DefaultFileRegion implements FileRegion {

	private final FileChannel file;
	private final long position;
	private final long count;
	private final boolean releaseAfterTransfer;

	public DefaultFileRegion(FileChannel file, long position, long count) {
		this(file, position, count, false);
	}

	public DefaultFileRegion(FileChannel file, long position, long count, boolean releaseAfterTransfer) {
		this.file = file;
		this.position = position;
		this.count = count;
		this.releaseAfterTransfer = releaseAfterTransfer;
	}

	public long getPosition() {
		return position;
	}

	public long getCount() {
		return count;
	}

	public boolean releaseAfterTransfer() {
		return releaseAfterTransfer;
	}

	public long transferTo(WritableByteChannel target, long position) throws IOException {
		long count = this.count - position;
		if (count < 0 || position < 0) {
			throw new IllegalArgumentException("position out of range: " + position + " (expected: 0 - " + (this.count - 1) + ')');
		}
		if (count == 0) {
			return 0L;
		}

		return file.transferTo(this.position + position, count, target);
	}

	public void releaseExternalResources() {
		try {
			file.close();
		} catch (IOException e) {
			// if (logger.isWarnEnabled()) {
			// logger.warn("Failed to close a file.", e);
			// }
			e.printStackTrace();
		}
	}
}
